Seager on the Empirical Case for Higher-Order Theories of Consciousness

In the recent second edition of William Seager’s book Theories of Consciousness: An Introduction and Assessment he addresses some of my work on the higher-order theory. I haven’t yet read the entire book but he seems generally very skeptical of higher-order theories, which is fine. Overall the argument he presents is interesting and it allows me to clarify a few things.

It is clear from the beginning that he is interpreting the higher-order theory in the standard relational way. This is made especially clear when he says that the basic claim of higher-order theory can be put as follows:

A mental state is conscious if and only if it is the target of a suitable higher-order thought (page 94)

This is certainly the way that most people interpret the theory and is the main reason I adopted ‘HOROR’ theory as a name for the kind of view I thought was the natural interpretation of Rosenthal’s work. I seem to remember a time when I thought this was ‘the correct’ way to think about Rosenthal’s work but I have since come to believe that it is not as cut and dry and that.

This is why I have given up on Rosenthal exegesis and just pointed out that there are two differing ways to interpret the theory. One of which is the relational kind of view summed up above. The other is the non-relation view, which I have argued allows us to capture key insights of the first-order theories. On this alternative interpretation the first-order state is not ‘made’ phenomenally conscious by the higher-order state. Rather the higher-order state just is phenomenal consciousness. Simply having the appropriate higher-order state is what being phenomenally conscious consists in, there is nothing more to it than that. This is the way I interpret the higher-order theory.

Seager comes close to recognizing this when he says (on page 94),

Denial of (CS) [the claim that “if S is conscious then S is in (or has) at least one conscious state”] offers a clear escape hatch for HOT theory. Contrast that clarity with this alternative characterization of the issue ‘[c]onscious states are states we are conscious of ourselves as being in, whether we are actually in them’ (Rosenthal 2002 p 415). Here Rosenthal appears to endorse the existence of a conscious state which is not the target of a higher-order thought, contrary to HOT theory itself. If so then HOT theory is not the full account of the nature of conscious states and it is time to move on to other theories. I submit that it is better for HOT theorists to reject (CS) and allow for creatures to be conscious in certain ways in the absence of an associated conscious mental state.

The quote from Rosenthal is an accurate one and it does summarize his views. If one interprets it my way, as basically saying that the higher-order state is the phenomenally conscious state, then we do have a conscious state that is not the target of a higher-order state (or at least which need not be). This is because the higher-order state is phenomenally conscious but not because of a further higher-order state. It is because being phenomenally conscious consists in being aware of yourself in the way the higher-order theory requires. As I have argued, in several places, this does not require that we give up the higher-order theory or adopt a ‘same-order theory’. HOROR theory is the higher-order thought theory correctly interpreted.

It thus turns out that phenomenal consciousness is not the same thing as ‘state consciousness’ as it is usually defined on the traditional higher-order theory. That property involves being the target of the higher-order state. This is something that, on my view, reduces to the causal connections between higher-order states, and their conceptual contents, and the first-order states. This will amount to a causal theory of reference for higher-order states. They refer to the first-order states which cause them in the right way. The states to which they refer are what I call the ‘targets’ of the higher-order states. So, for me the targeting relation is causal, but for Rosenthal and others more influenced by Quine it essentially amounts to describing. Thus for Rosenthal the target of the relevant higher-order state will be the first-order state which ‘fits the description’ in the higher-order content. I suppose I could live with either of these ultimately but I do think you need to say something about this on the higher-order account. At any rate on my view being the target of the higher-order state tells us which state we are aware of and the content of the higher-order state tells us the way in which we are aware of it. The two typically occur together but if I had to call one the phenomenally conscious state it would be the higher-order state.

Seager goes on to say in the next paragraph,

One might try to make a virtue of necessity here and seek for confirmation of the false HOT scenario. There have been some recent attempts to marshall empirical evidence for consciousness in the absence of lower-level states but with the presence of characteristic higher-order thoughts, thus showing that the latter are sufficient to generate consciousness (see Lau and Rosenthal 2011; Lau and Brown forthcoming; Brown 2015). The strategy of these efforts is clear: Find the neural correlates of higher-order thoughts posited by HOT theory, test subjects on tasks which sometimes elicit consciousness and sometimes do not (e.g. present them with an image for a very short time and ask them to report on what they saw), and, ideally, observe that no lower-order states occur even in the case where subjects report seeing something. Needless to say, it is a difficult strategy to follow. (page 95)

I would quibble with the way that things are put here but overall I agree with it. The quibbles come from the characterization of the strategy. What Lau and I were arguing was that we want to find cases where the first-order state is either absent or degraded, or otherwise less rich than the conscious experiences of subjects. So we would be happy just with a mis-match between the first-order and higher-order cases. Whether we ever get the ideal total absence of first-order states is maybe too high of a bar. This is why in the work that Lau does he aims to produce cases where task performance is matched but subjective reports differ. The primary goal is to show that conscious experience outstrips what is represented at the first-order level. It is a difficult strategy to follow but all we can do is to use the tools we have to try to test the various theories of consciousness.

Seager then goes on to focus on the case of the rare form of Charles Bonnett syndrome. In these rare cases subjects report very vivid visual hallucinations even though there is extensive damage to the primary visual cortex. Seager briefly considers Miguel Sebastian’s objection based on dreaming but then objects that

…a deeper problem undercuts the empirical case, tentative though it is, for HOT theory and the empty HOT scenario. This is a confusion about the nature of the lower-order and higher-order cognitive states ate issue. ‘Lower-order’ does not mean ‘early’ and ‘higher-order’ does not mean ‘later’ in the brain’s processing of information. Higher-order refers specifically to thoughts about mental states as such; lower-order states are not about thoughts as such but are about the world as presented to the subject (including the subject’s body).

There is little reason to think that lower-order states, properly conceived, should be implemented in low-level or entry-level sensory systems. It is not likely that an isolated occipital lobe would generate visually conscious states.

Nor is it unlikely that lower-order states, states, that is, which represent the world and the body occur in ‘higher’ brain regions such as the dorsolateral prefrontal cortex. It would be astounding if that brain region were devoted to higher-order thoughts about mental states as such. (page 96)

I largely agree with the points being made here but I do not think that Lau and I were confused about this. The first thing I would say is that we are pretty explicit that we adopt the usage that we think the typical first-order theorist does (and especially Ned Block) and that we include areas outside the occipital lobe “that are known to contain high number of neurons explicitly coding for visual objects (e.g. fusiform face area)” as first-order areas (see footnote 7 in the paper).

In the second instance we talked about three empirical cases in the paper and each was used for a slightly different purpose. When people discuss this paper, though, they typically focus on one out of the three. Here is how we summed up the cases in the paper:

To sum up, there are three kinds of Empirical Cases – Rare Charles Bonnet Cases (i.e. Charles Bonnet cases that result specifically from damage to the primary visual cortex), Inattentional Inflation (i.e. the results of Rahnev et al, in press and in review) and Peripheral Vision (introspective evidence from everyday life). The three cases serve slightly different purposes. The Rare Charles Bonnet Cases highlight the possibility of vivid conscious experience in the absence of primary visual cortex. If we take the primary visual cortex as the neural structure necessary for first-order representations, this is a straightforward case of conscious experience without first-order representations. In Inattentional Inflation, the putative first-order representations are not missing under the lack of attention, but they are not strong enough to account for the “inflated” level of reported subjective perception, in that both behavioral estimates of the signal-to-noise ratio of processing and brain imaging data show that there was no difference in overall quality or capacity in the first-order perceptual signal, which does not concern only the primary visual cortex but also other relevant visual areas. Finally, Peripheral Vision gives introspective evidence that conscious experience may not faithfully reflect the level of details supported by first-order visual processing. Though this does not depend on precise

laboratory measures, it gives an intuitive argument that is not constrained by specific experimental details.

So I don’t think Seager’s criticism of us as being confused about this is fair.

In addition, in recent work with Joe LeDoux we endorse the second claim made by Seager. We explicitly argue that the ‘lower-order’ states we are interested in will occur in working emory and likely even dorsal lateral prefrontal cortex.

But even if I think Seager is wrong to accuse us of being insensitive or confused about this issue I do think he goes on to present an interesting argument. He goes on to say,

The problem can be illustrated by the easy way HOT (or HOT-like) theorists pass over this crucial distinction. Consider these remarks from Richard Brown:

Anyone who has had experience with wine will know that acquiring a new word will sometimes allow one to make finer-grained distinctions in the experience that one has. One interpretation of what is going on here is that learning the new word results in one’s having a new concept and the application of this concept allows one to represent one’s mental life in a more fine-grained way. This results in more phenomenal properties in one’s experience…that amounts to the claim that one represents one’s mental life as instantiating different mental qualities.

Those unsympathetic to HOT theory will balk at this description. What is acquired is an enhanced ability to perceive or appreciate the wine in this case, not the experience of the wine (the experience itself does not seem to have any distinctive perceivable properties). After training the taster has new lower-order states which better characterize the wine, not new higher-order states aimed at and mentally characterizing the experience of tasting the wine.

Since there is no reason to restrict lower-order states to relatively peripheral sensory systems, it will be very hard to make out an empirical case for HOT theory and the empty HOT scenario in the way suggested. (pages 96-97)

The quote he offers here is from the HOROR paper and so it is interesting to see that the proposed solution, that the higher-order state is phenomenally conscious and that this is not giving up on the higher-order theory, is neglected.

Before going on I should say that I am pretty much sympathetic to the point being made here. I think there is a first-order account of what is going on. I also tend to think that this is ultimately an empirical issue. If there were a way to test this that would be great but I am not sure we have the capacity to do so yet. But my main point in the paper was not to offer this as a phenomenon that the first-order theorist couldn’t explain. What I was intending to do was to argue that the higher-order interpretation is one consistent interpretation of this phenomenon. It fits naturally with the theory and shows that there is nothing absurd in the basic tenet of the HOROR theory that phenomenal consciousness really is just a kind of higher-order thought, with conceptual content.

As I read Rosenthal he does not think the first-order account is plausible. For Rosenthal we are explicitly focusing on our experience sin these kinds of cases. One takes a drink of the wine and focuses on the taste of the wine. This may be done even after one has swallowed the wine. The same is true for the auditory cases. It does seem plausible that in these cases I am focused on my experience, not on the wine (it is the experience of the wine of course). But if the general kind of theory he advocates is correct then one will still come to appreciate the wine itself. When I have the new fine-grained higher-order thoughts they will attribute to me finer-grained first-order states and these will be described in terms of the properties I experience the wine as having. They will thus make me consciously aware of the wine and its qualities but they do so by making me aware of the first-order states. The first-order alternative at least seems to be at a disadvantage here because it seems that on their view learning the new word produces new first-order qualities as opposed to making me aware of the qualities which were already there (as on the higher-order view). I think there is some evidence that we can have ‘top down’ activity producing/modifying lower-order states so I ultimately think this is an empirical issue. At the very least I think we can say that this argument shows that the higher-order theory makes a clear, empirically testable predication, and like the empty higher-order state claim itself, the more implausible the prediction the more of a victory it is when it is not falsified.

At any rate abstracting from all of this Seager presents an interesting argument. If I am reading it correctly the claim seems to be that the empirical case for the higher-order theory is going to be undercut because first-order theories are not committed to the claim that first-order states are to be found in early sensory areas, and might even be found in places like the dlPFC. If so then even if there were a difference in activation there, as between early sensory areas, then this by itself would not be evidence for a higher-order theory because those may be first-order states.

The way I tried to get around this kind of worry (in my Brain and its States paper) was by taking D prime to be a measure of the first-order information which is being represented. This was justified, I thought, because the first-or-lower-order states are thought by us to largely drive the task performance. D prime gives us a measure of how well the subjects perform the task (by calculating the ration of hits to false alarms) and so it seems natural to suppose it gives a measure of what the first-order states are representing. The bias in judgment can be measured by C (the criterion) in signal detection theory and this can roughly be treated as a measure of the confidence of the subjects. So, instead of looking for direct anatomical correlates we can look for matched D prime scores while there is difference in subjective report. This is exactly what Lau and his lab has been able to show in many different cases. In addition when there is fMRI data it shows no significant difference in any first-order areas while there is a difference in the prefrontal cortex. Is this due to residual first-order states in ‘higher-order’ areas? Maybe, but if so they would be accounted for in the measure of D prime. And that would not explain why subjects report a difference in visibility, or confidence, or whatever. Because of this I do not think the empirical cases has been much undermined by Seager.

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